Azaborine as a versatile weak donor for thermally activated delayed fluorescence
Abstract
Extensive research has been devoted to the development of thermally activated delayed fluorescence emitters, especially those showing pure-blue emission for use in lighting and full-color display applications. Toward that goal, herein we report a novel weak donor, 1,4-azaborine (AZB), with complementary electronic and structural properties compared to the widely used dimethylacridan (DMAC) or carbazole (Cz) donors. Coupled with a triazine acceptor, AZB-Ph-TRZ is the direct structural analogue of the high-performance and well-studied green TADF emitter DMAC-TRZ and has ΔEST = 0.39 eV, a photoluminescence quantum yield (ΦPL) of 27%, and λPL = 415 nm in 10 wt % doped mCP films. The shortened analogue AZB-TRZ possesses red-shifted emission with a reduced singlet–triplet gap (ΔEST = 0.01 eV) and fast reverse intersystem crossing (kRISC of 5 × 106 s–1) in mCP. Despite a moderate ΦPL of 34%, OLEDs with AZB-TRZ in mCP showed sky-blue emission with CIE1931(x,y) of (0.22,0.39) and a maximum external quantum efficiency (EQEmax) of 10.5%. Expanding the chemist’s toolkit for the design of blue donor–acceptor TADF materials will enable yet further advances in the future, as AZB is paired with a wider range of acceptor groups.
Citation
Sudhakar , P , Kuila , S , Stavrou , K , Danos , A , Slawin , A M Z , Monkman , A & Zysman-Colman , E 2023 , ' Azaborine as a versatile weak donor for thermally activated delayed fluorescence ' , ACS Applied Materials & Interfaces , vol. 15 , no. 21 , pp. 25806-25818 . https://doi.org/10.1021/acsami.3c05409
Publication
ACS Applied Materials & Interfaces
Status
Peer reviewed
ISSN
1944-8244Type
Journal article
Description
Funding: H2020 Marie Sklodowska-Curie Actions - 891606, 812872; Engineering and Physical Sciences Research Council - EP/T02240X/1.Collections
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